Both sides of politics have ramped up public pressure over the carbon tax as one of the most divisive pieces of government policy in recent times officially begins.

From today, just under 300 businesses will be made to pay $23 for for every tonne of pollution they produce.

They will receive some compensation in the form of tax offsets and credits, but still say they will have no choice but to pass on the cost to consumers.

The Government is also compensating low-income earners and says life will go on for Australian households.

But the Opposition argues it the tax is an unnecessary burden during tough economic times, and is rolling out an advertising campaign that highlights Prime Minister Julia Gillard's policy reversal.

Ms Gillard announced before the 2010 election that there would be no carbon tax under a government she led.

Today she again defended her decision to introduce a carbon tax, telling the ABC's Insiders program that putting a price on carbon will help protect the environment and strengthen the economy.

Opposition Leader Tony Abbott has promised to repeal the tax if the Coalition wins government, but Ms Gillard compared the carbon tax to the GST introduced by the Howard government, saying that once it was in operation it it was clear that there was no going back.

Ms Gillard says at the time she was very concerned about how the GST would impact households, but that Australians came to accept it.

"People have already seen pension increases and family payment increases and family payment increases and this assistance to families around the country will continue. Businesses have got themselves ready for carbon pricing. New investments are being made," she said.

But Mr Abbott maintains the carbon tax will have a negative impact on the Australian economy.

He told the Liberal Party's national conference in Melbourne yesterday that the Australian public can be "100 per cent certain" when he says there will be no carbon tax under a government he leads.

"It will raise every family's cost of living, it will make every job less secure but it won't help the environment," he said.

"Australia's domestic emissions will be 8 per cent higher, yes, higher by 2020 despite a carbon tax of $37 a tonne."

Today Mr Abbott reiterated he would repeal the carbon tax if the Coalition wins government.

He said the first item the Coalition would put before the parliament would be legislation aimed at removing carbon pricing.

Greens Leader Christine Milne has dismissed the idea that her party may have misplaced their efforts in negotiating the carbon tax with a Gillard minority government.

She echoed sentiment from the Prime Minister, saying Mr Abbott will not repeal the carbon tax if he takes government.

"Contrary to all Tony Abbott's claims, it won't be repealed in Australia and it is going to be his problem as to how he backs down or how the Liberals change their leadership," she said.

"It is an exciting day in Australia because this is it the day that we begin to seriously tackle global warming and to price pollution.

"We're going to see is quite a lot of innovation across Australia and you're going to see households, industries, people going out there creating new jobs, new ideas, and this is really the beginning of a much more positive future."

Nationals Leader Warren Truss says the carbon tax is not a "drop-dead event" but it is already hurting business confidence.

Mr Truss says business will become less competitive and less willing to to take on new staff.

"[The carbon tax] is the slow boa constrictor sapping life out of one business after another," he said.